Drafting lead point shaper



0r.21, 1952 A EHROCKS 2,614,534

DRAFTING LEAD POINT vSHPER Filed Jan. 25, 1950 "tu l MUNI i MU' WUH- INVENTOA Patented Oct. 21, 1952 UNITED STATES PATENT OFFICE DRAFTING LEAD POINT SHAPER Ewalt H. Rocks, Racine, Wis.

Application January 25, 1950, Serial No. 140.467

(Cl. L- 96) 5 Claims. l

The present invention relates generally to improvements in the art of precision grinding, and relates more specifically to improvements in Ithe construction and operation of mechanism for shaping the end portions of thin and relatively brittle elongated cylindrical elements such as drafting leads confined within a holder or handle.

The primary object of my invention is to provide an improved lead point shaper which is simple and compact in construction, and which also functions with utmost precision to produce points of any predetermined shape or contour.

Various types of so-called pencil Sharpeners for renewing broken or worn pencil points with the aid of rotary cutters and abrasive wheels have heretofore been utilized for many years, but none of these mechanisms is adapted to produce lead points of desired shapes with any degree of accuracy such as required for different kinds of drafting and lettering. While it has previously been proposed to sharpen ordinary wooden pencils with the aid of a gear driven rotatable abrasive disk cooperable with a rotary pencil guide disposed tangent to the disk, and wherein the disk was axially movable to grind off more or less of the wood and lead, this prior Sharpener was not operable to precisely reproduce specific styles or shapes of lead points adapted for particular uses, and therefore rnever became popular for drafting room and illustrating services.

It is therefore an important object of my present invention to provide a pencil lead point Sharpener especially adapted for use by draftsmen, illustrators, and artists, and which may be preset to accurately reproduce points of any desired shape, contour, or thickness.

Another important object of this invention is to provide an improved motor driven drafting lead pointer which is conveniently operable to quickly and effectively shape new lead points or to restore worn points to `any predetermined condition especiallyl adapted for the duty for which they are intended. c n

A further important object of the invention is to provide an improved lead point shaping unit which is conveniently manipulable to produce points of definite pre-selected contour, which is motor driven to rapidly perform its intended function, and which may be readily mounted in any desired position and locality.

Still another object of my invention is tovprovide a precision lead point shaping device which is highly dependable in operation, all parts of which are readily accessible for inspection and CIE cleaning, and which may be manufactured and sold at moderate cost.

These and other objects and advantages of the invention will be apparent from the following detailed description.

A clear conception of the features ,constitutingv my present improvement, and of the construc-y,v tion and operation of a typical pencil lead pointr shaping unit embodying theinvention, may be had by referring to the drawing accompanying and forming a part of this specification wherein like reference characters designate the same or similar parts in the various views. y

Fig. l is a top view of a motor driven pencil.

point Shaper showing the location of the motor within the casing of the unit in dotted lines;

Fig. 2 is an end view of the same unit looking;

toward the pencil applying end, and showingthe devices mounted upon a support;

Fig. 3 is a central longitudinal section through the same assemblage, but showing the motor in elevation; v y

Fig. 4 is a fragmentary section similar to that of Fig. 3 but showing a. modified pencil and lead guide; and c Fig. 5 is a view showing three typical consid-` erably enlarged point shapes which may bepro-` duced With the improved unit.

The important feature of 4the present'.inven-y4 tion is the provision of simple and effective means for enabling accurate production of various dfinite lead point shapes, and of effecting precise reproduction of any selectedpoint thicknessor contour bydraftsme'n or others having al favorite type of pointwhich they` prefer t0 utilizefor cer-r tain classes of work.

Referring to the drawing, theimpoved draf-t'- ing lead point shaping unit shown therein coinprises in general a `mainhousing or casing consisting of a medial frame section 8 and two op'- positely disposedcup-shaped coversl 9, l0 coacting with the central section.- 8; a rotor Il.r ro-QV tatably confined within" the coverl 9 and having" an abrasive side surface I2 disposedr approxitheabrasive rotorrsurface l2; a micrometer adjusting member 2I having screw threads 22 coacting With an internally threaded tubular flange 23 formed on the cover I0 and engaging one end of the shaft I5 to move this shaft in one direction; and a leaf spring 24 secured to the frame 5 section 8 and cooperating with the fitting I6 and with the opposite end of the shaft I5 to constantly urge the latter toward the member 2I.

The frame section 8 may be formed of any durable metal and has an outwardly projecting 10 integral boss 26 screw threaded for the reception of a stud 21, and a clamping jaw 23 and wingy nut 29 may be caused to cooperate with the stud' 21 in order to firmly mount the unit Vupon -a sup.-

port 30 as shown in Fig. 2. The mid-section 8 l5 of the casing provides a partition wallV 32 spanning the casing interior, andthe motor shaft I5 extends through this wall 32 and is preferably provided with a flexible packing 33 at thefpoint of penetration of the partition so as to prevent 20 dust: from escaping from the grinding .chamber into the motor confining chamber of the' houslng.A -The .framewall 32 also has a llarge lateral projection 35formed integral. therewith and `extending into the cover 9 and to which' the pencil 25 andi-lead'g'uide I9 is adjustably attached by a retaining screw-36 as depicted in Figs. 2 and 3, and l-the-leaffspring 24 may valso be secured to this rigid# projection by means of another screw "31.- -The partition wall 32 is furthermore 30 abrasive rotor'cover 9 has an opening 42 therein 40 adapted LYto be hooked over the vouter end of the normally fixed guide I9, and this cover may be detachablyclampedto the frame-bosses'38 by meansd of wing *screws- 43 so as to seal the grinding zone while still permitting convenientre- 45 movalof dust producedv during normal operation of Vtheunit.A Thev motorcover I0 is-also firmlybutl detachably secured to the frame bosses* 39 Aby meansofstuds 44 and nuts--45 coactingthere- Withrand besides'providing aA mounting for the 50 rotorv shaftadjustingwfmember' 2I, this'cover I0 supportsra, push buttonfswitch46 for 'con-f trollingtheoperation of the motor I4 and is also "providedwith a conductor0 bushing 44l for the'electrie wires'48 which supply'current to the 55 motor I4 through the switch 46.

Theelectricmotor -I4 Which'ls rmly secured tothe vframe section '8' by means of studs'and' nuts" 50, may be Vof anysuitable construction,

either alternating or direct current; and maybe placed' in operation 'to rotate the'shaft I5 by pressing the button of the switch' 46 but will'stop quickly when this button is released'by virtueof theend pressure exerted upon this shaft I5 by connectedto the motor shaftr i5 by a screw 5I, andthe rotor'iII maybe eitherV an abrasive'eutting wheel or may merely haveabrasive opposite` side cutting surfaces" I2 so that thisrotor-Y I'I may be reversibly clamped to the; fitting YIIS with" theaidof the clamping nutA I1 and a lock washer;

The specific; and accurate formationv or shapeof the rotor4 side surfaces I2 is an impor-i-` tantA featureof thepresent invention; and "as shownin Flgi; onesidesurfaceof the rotor IIv I0 may be 35 is substantially plane while the opposite side is provided with an annular fillet having rather abrupt concave curvature near the rotor axis and with a gradually slightly tapered annular surface extending outwardly from near the abrupt curvature. The plane side surface of the rotor II may be utilized to produce truly conical lead points 20 or points having ilat opposed surfaces. while the other side surface I2 may be used to form relatively blunt tipped points 20 preferably having tapered portionsI merging with cylindrical portions directly adjoining the rounded tips, as illustrated, and the diameters of these points may be positively predetermined and varied by setting the rotor II nearer to or furtherfrom the inclined pencil and lead guide I9 while the point shape may be varied by changing the contour of the rotor side surfaces.

The micrometer adjustment for setting the rotor II in any preselected position relative to the guide I9 and which consists primarily of the -member 2| having screw threadcoaction with the annular flange 22 of the casing cover. I0, vis also an importantfeature of my invention.r

The threadedy membery 2l is adjustableto move the shaft` I5 andtherotor II axially toward the` guide IS, by means of an oscillatory arm 52 one end of which is secured to the member 2| by a nut 53 and the opposite end of which projects laterally over the cover I0 and acts as a'pointer co,

operating` with a seriesv of markings 54 applied to Athe. adjacent outer surfacezof thisxcover, .as

shown in Fig. l. A relatively stiff-helical compres.

sion spring 55 Vsurrounds the member. 2| and presses against the cover IU and lever arm 52 so as to hold this arm` in any desired position of adjustment, while still permitting convenient:

swinging of the arm to vary the'diameterrof the points 23 which are-to be formed, and the rela'-` tively-stiileaf-spring 24 coacting with the iittingr I6 serves to moveethe rotor II and theshaft I5 axially away from thefguide I9 and to maintainv the inner end` of the holder 51 to arrest the in-A ward advancementthereofis shown -in Fig. 3 as being-merely axially adjustable in order to produce -lead points of any predetermined length, this-guide may also be made swingably adjustabletoA furthervary the shapes of the lpointsl produced, as shown -in Fig; 4. HereV the guidel I9' is provided with `a flat side surface 5B, and

in addition to the-mainclamping screw^36 coact ing with this surface 58 an auxiliary retaining screw'59 is provided. By maintaining the screw 36 inclamping position and temporarily `loosening the screw 59, the guide I9 maybe swungslightly in either direction about the main screw y38 as a pivot; 'andiby likewise loosening both screws 35,;'59 the guide I9 may be axially adjusted. Thls modified structure therefore 'provides' an extra means for varying the point shapeor contour, in addition to the formation of theY rotor' side surface I2; but in either case the bottom of the guide provides Aan abutment forpositivelyfarresting the inward movement of the holder 51 and thus always insures the production of lead points of definite length,

During normal use of the improved point shaping unit, it should first be mountedupon a suit` able support 30 as shown in Fig. 2 and theplug 60 should be applied to source of electric current;

The lever arm 52 should then be set to cooperate with the marking 54 corresponding to the type of point which it is desired to produce. The pencil or holder 51 may then be inserted within the guide I9 and the lead 20 may be caused to lightly contact the effective rotor side surface I2 whereupon the switch I6 may be operated to start the motor I4 and to thereby rotate the shaft I5 and revolve the rotor II. Then by gradually urging the lead holder 51 forwardly until its end is arrested by the guide bottom as in Fig. 3, and by simultaneously rotating it within the guide I9, a point 20 of the desired shape, length and diameter will be quickly and accurately prou duced.

The opposite abrasive side surfaces I2 of the rotor II may be formed with different contours so that by reversing this rotor I I upon the fitting I6 points 20 of different contours may be pro duced, and by adjusting the arm 52 so as to point to different markings d points of different diameters may also be produced, Additional rotors II having considerable variation in the shape of the abrasive or cutting surfaces I2 may be provided, and considerable change in the angularity of the guide I9 may also be effected, in order to produce points 2d of any desired contour. The abrasive surfaces I2 may in fact be far more steeply inclined relative to the rotor axis and may even be peripheral rotor surfaces, while the axis of the guide I9 may also be disposed substantially parallel to the rotor axis. A few typical point shapes 2li, 2li', 26 are illustrated in Fig. 5 but obviously many others are possible, and the motor I4 may be stopped by I merely releasing the switch 4G.,

After the unit has been in use for some time, the cover 9 should be removed by releasing the screws 43 in order to effect removal of aocumu lated lead dust; and the cover IE! should also be occasionally removed by releasing the nuts 45 so that the motor bearings may be lubricated. Since the member 2l merely contacts the shaft I5 and is not attached thereto, such removal vof the cover IU is readily possible. When an adjustment of the rotor II in order to decrease the point diameter is made, the micrometer member 2l pushes the rotor II and the shaft l5 toward the guide I9 by slight increments precisely the desired amount; but when the setting is such as to enlarge the point diameter, then the leaf spring 24 functions to push the rotor and shaft in opposite direction.

From the foregoing detailed description of the construction and operation of a typical lead shaping unit embodying the present invention, it should be apparent that I have in fact provided a simple and compact mechanism for producing lead points 2U, 2li', 20 of diverse accurately performed contours with utmost precision. By locating the pointer end of the adjusting arm 52 closely adjacent to the switch 45, manipulation of the unit is facilitated, and by rotating the lead holder 51 continuously circular points 25 may be produced, while fiat or polygonal points may also be produced by lifting the holder 57 away from the rotor II and intermittently only partially rotating the same. All parts of the improved unit may be easily and accurately constructed and assembled at moderate cost to provide a durable and attractive assemblage which is readily attachable to a support 3D, and the invention has proven highly satisfactory and successful in actual use. While this improved device is not an ordinary pencil Sharpener, it has extreme utility especially for draftsmen and illustrators who require utmost precisionand accuracy in the formation and shaping of lead points confined within lead holders 51.

I claim:

l. In a Shaper for pencil leads confined within a holder, a rotor having an annular lead reducing side surface generated by revolving a radial line disposed at an oblique angle relative to the rotor axis about said axis and also having an annular llet surrounding said axis and mergnig with the inner edge of ysaid surface, means for rapidly revolving said rotor about said axis. and a guide cooperable withsaid holder to direct each lead longitudinally and across said surface against said niiet, said guide having an abutment cooperable with the end ofthe holder to produce finished points of definite length and of predetermined shape each having a tip following the fillet contour and ay taper receding from said tip and following the contour of said surface.

2. In a shaper for pencil leads confined within a holder, a rotor having an annular lead reducing side surface generated by revolving a radial line disposed at an oblique angle relative to the rotor axis about said axis and also having an annular fillet surrounding said axis and merging with the inner edge of said surface, means for rapidly revolving said rotor about said axis, and a guide cooperable with the holder to direct each lead longitudinally and radially with respect to the rotor axis across said surface against said fillet the bottom of said guide being cooperable with the inner end of the holder to produce iinished points of definite length and of predetermined shape each having a tip following the fillet contour and a taper receding from said tip and following the contour of said surface.

3. In a Shaper for pencil leads confined within a holder, a rotor having an annular lead reduc ing side surface generated by revolving a radia line disposed at an oblique angle relative to the rotor axis about said axis and also having an annular fillet surrounding said axis and merging with the inner edge of said surface, means for rapidly revolving said rotor about said axis, and a guide cooperable with the holder to direct each lead longitudinally and across said surface` against said fillet, said guide having a bottom abutment cooperable with the inner end of the holder to positively arrest the inward travel of the lead to produce finished points of denite length and of predetermined shape each having a tip following the fillet contour and a taper receding from said tip and following the contour of said surface.

4. In a shaper for pencil leads confined within a holder. a rotor having an annular lead reducing side surface generated by revolving a radial line disposed at an oblique angle relative to the rotor axis about said axis and also having an annular llet surrounding said axis and merging with the inner edge of said sulrface, means for rapidly revolving said rotor about said axis, a guide cooperable with said holder to direct each lead longitudinally and across said surface against said fillet to produce finished points of definite predetermined shape each having a tip following the fillet contour and a taper receding from said tip and following the contour of said surface, means associated with said guide for positively arresting the inward movement of the holder to produce points of definite length, and means for adjusting the position of said guide relative" to said krotor Asidesurface .tovary -either the` thickness .orrtlie' taper or. thepredetermined l* lengthi of the leadipoints. f

5. In a shaper'for pencil Vleads conflnedwithin a holder, a rotor having an annular lead reducingrside'surfa'cegenerated by revolving apradial line' disposed VVai; an oblique: 'angle relative tothe V'rotor f'axisf about said` axis v and merging Vdirectly in' thevouter edge of an annulartreducingsurface disposed perpendicular' to zsaid axis and' thezinner edge offrwliich' in turnlmerges dre'ctly'iwithan "annulaix lfillet surrounding. saicLaxis,V` means'for .rapidlyfrevolving 'said'. rotor. about" saidl axis, and axguide coope'rabie' with theholder to. drecteach r lead'.` longitudinally: andtradiallyf across. said.V surlfaces 'against' said. ilet tosproduc nishedtpoints 1 ofLdenite'shapet eachah'aving a; Acipifollowing .the i iiilet: .contounfand successive; 'cylindrical'and etapezed; surfaces'receding from. said: tip, fand :i means?A asscuciated Withrsa'id '.guide: for po'sitively 8 f arresting eine. :.inwardzmovementfof the rholder rat aedenite locality.

QEWALT'LELE ROCKS.

REFERENCES. CITED The followingreferencesL are of'recordinthe YIileof this'patent:

vUNITED STTES PATENTS 

